Should able to select only one radio button from the grid

a!forEach(
items: local!empCriteria,
expression: a!columnsLayout(
columns: {
a!columnLayout(
contents: {
a!dropdownField(
label: "Employee Dept",
labelPosition: "COLLAPSED",
placeholder: "--- Select a Value ---",
choiceLabels: CONS!EMPDEPTLABELS,
choiceValues: cons!EMPDEPTVALUES,
value: fv!item.employeeDept,
saveInto: fv!item.employeeDept,
searchDisplay: "AUTO",
required: true(),

)
}
),
a!columnLayout(
contents: {
a!radioButtonField(
label: "Sort On",
labelPosition: "COLLAPSED",
choiceLabels: { "Yes" },
choiceValues: {true()},
value: fv!item.sortOn,
saveInto: fv!item.sortOn,
choiceLayout: "STACKED",
validations: {}
)
},
width: "EXTRA_NARROW"
),
a!columnLayout(
contents: {
a!dropdownField(
label: "Operator",
labelPosition: "COLLAPSED",
placeholder: "--- Select a Value ---",
choiceLabels: cons!OPERATORS,
choiceValues: cons!OPERATORS,
value: fv!item.operator,
saveInto: fv!item.operator,
searchDisplay: "AUTO",
validations: {},
required: true(),

)
}
),
a!columnLayout(
contents: {
a!dropdownField(
label: "AND / OR",
labelPosition: "COLLAPSED",
placeholder: "--- Select a Value ---",
choiceLabels: { "AND", "OR" },
choiceValues: { "AND", "OR" },
value: fv!item.gate,
saveInto: fv!item.gate,
searchDisplay: "AUTO",
validations: {},
required: true(),

)
}
)
}
)
),
a!buttonArrayLayout(
align: "END",
buttons: {
a!buttonWidget(
label: "Search",
submit: true,
saveInto: {
a!save(
ri!empCriteria,
local!empCriteria
),
a!save(ri!button, "Search"),

},
style: "PRIMARY",
loadingIndicator: true,

),
a!buttonWidget(
label: "Exit",
value: "Exit",
saveInto: ri!button,
submit: true,
style: "NORMAL",
validate: false
)
}
)

I should able to select only on radio button out of five rows on the grid.For example if I select sortOn radio button on 3rd row and switch to 1st row then 3rd row radiobutton should be unselected and only 1st row radiobutton should act selected.